1. Field of the Invention
This invention relates to an image processing method and an image processing apparatus for carrying out image processing such as gradation processing, frequency processing, temporal subtraction processing or metering processing on medical image data representing a medical image such as a radiation image or a magnetic resonance image on the basis of the object part thereof and/or the direction of taking the image. This invention also relates to a program for causing a computer to execute the image processing method.
2. Description of the Related Art
Recently, DICOM (Digital Imaging and Communication in Medicine) standard has come to be used as a standard for medical image transfer. Since the DICOM standard supports TCP/IP protocol for the current internet, use of the DICOM standard permits apparatuses made by different makers to transfer therebetween information on patients and/or medical image data by way of a network, whereby problems inherent to the conventional diagnosis mainly based on the photographic films (e.g., on the storage of the photographic films or the delivery speed) can be overcome and additional values can be expected.
The medical image data transferred in an open network environment using such DICOM standard is generally attached with photographing information representing the object part (e.g., head, chest or abdomen) thereof and/or the direction of taking the image (e.g., from the front, from a side or the like) as well as the file name, the size and the like of the medical image data as attendant information. Kinds of image processing and image processing parameters suitable for the object part and/or the direction of taking the image are selected on the basis of the photographing information attached to the medical image information. Then the medical image data is subjected to image processing such as gradation processing, frequency processing, dynamic range compression processing and the like. The photographing information sometimes used for selecting a plurality of radiation images, whose object parts and/or directions of taking the image are the same, to be compared with each other. The selected radiation images are sometimes displayed side by side to facilitate comparison of the radiation images and are sometimes subjected to an inter-image operation such as temporal subtraction processing where subtraction is carried out between corresponding pixels of the radiation images. Further, the photographing information sometimes used for selecting a radiation image to be subjected to metering processing for measuring the degree of scoliosis or the cardiothoracic ratio or to computer aided diagnosis of medical images in which prospective abnormal shadows are automatically detected by the use of computer processing.
However, in the open network environment using such DICOM standard, depending on the apparatus by which the medical image data is obtained, the medical image data is sometimes not attached with photographing information. It has been difficult to carry out an optimal image processing on such medical image data. Though the operator who carries out image processing can attach photographing information to the medical image data by viewing an image reproduced on the basis of the medical image data and recognizing the object part and/or the direction of taking the image, it is very troublesome.